Unless of course his intent was to draw attention to the fact that this is going to become a major problem, and soon, due to the absence of regulation around drone airspace, in which case, success!
Success? Sounds like a good way to get in trouble in more ways than one. I don't think I would have been as gracious as "ok I'm going to go call the police".
Even if he was trying to bring the issue to light... there has got to be better ways then potentially getting your ass kicked by strangers.
And if flying the drone is legal, you would have been taken to jail for assault, thereby turning the man into a martyr. You can't kick someone's ass out of the blue for doing something that's perfectly legal to do.
Yeah, but he bugged out and remains unidentified, so it remains perfectly possible that this was an attempt to draw media attention to the problem of drone surveillance.
Then again, it could be some dude who's discovered that he can remotely perv on people, in which case, this is still a general success, as it draws attention to the problem of drone surveillance.
Sounds like some pretty irresponsible "research".
Even if the intent is utterly benign, it's pretty easy to see how this could end badly. I'd say drone-man lucked out if this is how it all went down.